Punch die and punch machine using the same

ABSTRACT

An exemplary punch die ( 30 ) includes a lower die ( 40 ) and an upper die ( 50 ). The lower die includes a die core ( 45 ), a blank holder ( 417 ), and a cylinder ( 413 ) disposed in the lower die. The blank holder is disposed on a periphery of the die core. The cylinder is connected to the blank holder and provides a constant force to the blank holder. The upper die includes a punch core corresponding to the die core. A punch machine using the present punch die is also provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to punch dies and, more particularly, to apunch die for a punch machine.

2. Discussion of the Related Art

Referring to FIG. 3, a related-art punch die 10 includes an upper die 12and a lower die 14. The punch die 10 is generally installed on a punchmachine 20, and configured to punch a metallic workpiece. The punchmachine 20 includes a base set 22, and a bracket 24 supported by thebase set 22. The upper die 12 is attached to the bracket 24, and can bemoved downwards by a first cylinder 242. The lower die 14 is disposed onthe base set 22. A blank holder 16 is sleeved on the base set 22. Asecond cylinder 222 is disposed in the base set 22. The second cylinder222 is connected to the blank holder 16 for providing a constant forceto the blank holder 16.

The second cylinder 222 is disposed in the base set 22. When the secondcylinder 222 breaks down, the punch machine 20 should be hoisted up sothat the second cylinder 222 can be taken out of the base set 22 forrepairing. As such, it is very cumbersome to repair the second cylinder222. Thus, the blank holder 16 is generally replaced by a spring or anair cushion that is easily disassembled. When a metallic workpiece ispunched, the spring or the air cushion applies a force to the metallicworkpiece. The force is related to a force provided by the secondcylinder 222 and the compression of the spring or the air cushion. Sincethe compression of the spring or the air cushion is often inconstant,the force applying to the metallic workpiece is unstable, which leadsthe punched workpiece to have an unstable size.

Therefore, a punch die and a punch machine using the same which iseasily repaired and can punch a workpiece with a stable size.

SUMMARY

In one aspect, a punch die includes a lower die and an upper die. Thelower die includes a die core, a blank holder, and a cylinder disposedin the lower die. The blank holder is disposed on a periphery of the diecore. The cylinder is connected to the blank holder and provides aconstant force to the blank holder. The upper die includes a punch corecorresponding to the die core.

In another aspect, a punch machine includes a base set, a bracketdisposed on the base set, a driving device disposed on the bracket, anda punch die. The punch die includes a lower die and an upper die. Thelower die includes a die core, a pressing member, and a cylinderdisposed in the lower die. The pressing member is disposed on aperiphery of the die core. The cylinder is connected to the pressingmember and provides a constant force to the pressing member. The upperdie includes a punch core corresponding to the die core. One of thelower die and the upper die is placed on the base set of the punchmachine, the other is fixed to the bracket, and driven by the drivingdevice.

Other advantages and novel features will become more apparent from thefollowing detailed description when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily drawn to scale, theemphasis instead being placed upon clearly illustrating the principlesof the present a punch die and a punch machine using the same. Moreover,in the drawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a cross-sectional, schematic view of a punch die in accordancewith an exemplary embodiment.

FIG. 2 is a schematic view of a punch machine with a cross-sectionalview of the punch die in FIG. 1.

FIG. 3 is a schematic view of a related-art punch die.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIG. 1, a punch die 30 used to punch a workpiece is shown.The punch die 30 includes a lower die 40 and an upper die 50. The lowerdie 40 includes a pressing assembly 41, a die set 42, a lower paddingplate 43, a die holder 44, a die core 45, and a plurality of fixingmembers (not shown).

The pressing assembly 41 includes a supporting plate 411, a sleeve 412,a cylinder 413, a top plate 414, two top rods 415, a baffle plate 416,and a blank holder 417. The sleeve 412 is fixed to the supporting plate411. The cylinder 413 is disposed in the sleeve 412, and fixed to thesupporting plate 411. The cylinder 413 is a thin type cylinder, andincludes a main body 4131 and a piston rod 4132. The main body 4131 isconfigured to provide an adjustable and constant force to the piston rod4132. The top plate 414 is received in the sleeve 412, and is fixed tothe piston rod 4132.

The die set 42 defines two through holes 422 for the top rods 415 toextend through. A plurality of guiding posts 47 are fixed to a topsurface of the die set 42.

The lower padding plate 43, the die holder 44, the baffle plate 416, andthe blank holder 417 are substantially rectangular, and are disposed onthe die set 42 in that order. The lower padding plate 43 defines a pairof assembly holes 431 for the top rods 415 to extend throughcorrespondingly. The die holder 44 defines a fixing hole (not labeled)for the die core 45 to extend through, and two assembly holes 442 forthe top rods 415 to extend through correspondingly. The lower paddingplate 43 and the die holder 44 are fixed to the die set 42 via thefixing members.

The baffle plate 416 defines a through hole 4161 in a middle portion.The blank holder 417 defines a through hole 4171 in a middle portion.The through holes 4161, 4171 are configured for the die core 45 toextend through. The baffle plate 416 is fixed to the blank holder 417via the fixing members. One end of each top rod 415 is attached to asurface of the top plate 414. The other end of each top rod 415 ispassed through the die set 42, the lower padding plate 43, the dieholder 44, and then fixed to the baffle plate 416. The die core 45 isdisposed in the fixing hole of the die holder 44, and fixed to the lowerpadding plate 43 via the fixing members. The baffle plate 416 and theblank holder 417 are sleeved on the die core 45. The cylinder 413 drivesthe baffle plate 416 and the blank holder 417 to move relative to thedie core 45.

The upper die 50 includes a punch set 51, an upper padding plate 52, apunch plate 53, a punch core 54, and a plurality of the fixing members(not shown). The punch set 51 is substantially rectangular. A pluralityof outer bushes 57 are fixed to a surface of the punch set 51. Eachouter bush 57 defines a dowel hole 572 for engaging with one of theguiding posts 47.

The upper padding plate 52 is fixed to a surface of the punch set 51 viathe fixing members, and the punch plate 53 is fixed to the upper paddingplate 52 via the fixing members. The punch plate 53 defines a holdinghole (not labeled). The punch core 54 is received in the holding hole,and is fixed to the upper padding plate 52. The punch core 54corresponds to the die core 45, and defines a cavity 541 for engagingwith the die core 45. The width of the cavity 541 is lager than that ofthe die core 45.

Referring also to FIG. 2, a punch machine 70 includes a base set 71, abracket 72, and the punch die 30. A driving device 721 and a guiding rod722 connected to the driving device 721 are disposed on the bracket 72.The supporting plate 411 of the lower die 40 is placed on and fixed tothe base set 71. The punch set 51 of the upper die 50 is fixed to theguiding rod 722.

When a metallic workpiece 80 is punched, the top surface of the blankholder 417 and the top surface of the die core 45 are adjusted to a sameplane. The metallic workpiece 80 is placed on the die core 45. The upperdie 50 is driven by the driving device 721 and moves downwards. When thedriving device 721 moves downwards, the dowel holes 572 sleeves onto theguiding posts 47, and, as a result, the upper die 50 moves downwards,the guiding posts 47 protrudes into the dowel holes 572 of the outerbushes 57. When the punch plate 53 of the upper die 50 contacts themetallic workpiece 80, the cylinder 413 actuated, thereby creating aconstant force that pushes the piston rod 4132 upwards. The constantforce pushes the blank holder 417 upwards via the top plate 414, the toprods 415, and the baffle plate 416. Thus, the workpiece 80 becomesclamped between the blank holder 417 and the punch core 54. After that,the upper die 50 moves downwards further, and pushes the blank holder417 and the baffle plate 416 to move downwards. The workpiece 80 ispartially pressed into the cavity 541 of the punch core 54 until theworkpiece 80 is stamped into a predetermined shape.

In alternative embodiments, there may be more than two top rods 415connected to the blank holder 417. The number of the die cores 45 may betwo or more than two. In such cases, the number of the punch core 54 ofthe upper die 50 corresponds to the number of the die core 45. A blankholder 417 is sleeved on each die core 45. Each blank holder 417 isdriven by a corresponding cylinder 413. Alternatively, the lower die 40of the punch die 30 may be fixed to the guiding rod 722. In suchcondition, the upper die 50 is placed on and fixed to the base set 71.The blank holder 417 may be other pressing members, such as a pressingwasher.

It should be understood that, since the cylinder 413 is disposed in thepunch die 30, when the cylinder 413 breaks down, the cylinder 413 iseasily taken out for repairing. The cylinder 413 provides a constantforce to the blank holder 417. Thus, the blank holder 417 applies theconstant force to the metallic workpiece 80, which leads the punchedworkpiece to have a stable size.

It is believed that the present embodiments and their advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the invention or sacrificing all of its materialadvantages, the examples hereinbefore described merely being preferredor exemplary embodiments of the invention.

1. A punch die, comprising: a lower die including a die core, a pressingmember, and a cylinder disposed in the lower die, the pressing memberbeing disposed on a periphery of the die core, the cylinder beingconnected to the pressing member for providing a force to the pressingmember; and an upper die including a punch core corresponding to the diecore.
 2. The punch die as claimed in claim 1, wherein the lower diefurther comprises a die set, a lower padding plate, and a die holder,the lower padding plate and the die holder are fixed to the die set inthat order, the die holder defines a fixing hole, the die core isreceived in the fixing hole of the die holder, and fixed to the lowerpadding plate.
 3. The punch die as claimed in claim 2, wherein the upperdie further comprises a punch set, an upper padding plate, and a punchplate, the upper padding plate is fixed to the punch set, a punch plateis fixed to the upper padding plate, the punch plate defines a holdinghole, the punch core is received in the holding hole and fixed to theupper padding plate.
 4. The punch die as claimed in claim 3, wherein aplurality of guiding posts are fixed to a top surface of the die set, aplurality of outer bushes are fixed to a surface of the punch set, eachouter bush defines a dowel hole for engaging with one of the guidingposts.
 5. The punch die as claimed in claim 1, wherein the lower diefurther comprises a supporting plate and a sleeve, the supporting plateand the die set are disposed on opposite sides of the sleeve, and thecylinder is received in the sleeve and fixed on the supporting plate. 6.The punch die as claimed in claim 5, wherein the pressing member issleeved on the die core, the cylinder includes a main body and a pistonrod, the lower die further includes a top plate and a plurality of toprods, the top plate is fixed to the piston rod, the top rods are fixedto the top plate, the top rods are passed through the die set, the lowerpadding plate, and the die holder in that order, and then connected tothe pressing member.
 7. The punch die as claimed in claim 6, wherein thelower die further comprises a baffle plate, the baffle plate is sleevedon the die core and fixed to the top rods, the pressing member is fixedto a surface of the baffle plate adjacent to the upper die.
 8. The punchdie as claimed in claim 1, wherein the cylinder is a thin type cylinder.9. A punch machine, comprising: a base set; a bracket disposed on thebase set; a driving device disposed on the bracket; and a punch die, thepunch die including: a lower die including a die core, a pressingmember, and a cylinder disposed in the lower die, the pressing memberbeing disposed on a periphery of the die core, the cylinder beingconnected to the pressing member for providing a constant force to thepressing member; and an upper die including a punch core correspondingto the die core, one of the lower die or the upper die being placed onthe base set of the punch machine, the other being fixed to the bracket,and driven by the driving device.
 10. The punch machine as claimed inclaim 9, wherein the lower die further comprises a die set, a lowerpadding plate, and a die holder, the lower padding plate and the dieholder are fixed to the die set in that order, the die holder defines afixing hole, the die core is received in the fixing hole of the dieholder, and fixed to the lower padding plate.
 11. The punch machine asclaimed in claim 9, wherein the lower die further comprises a supportingplate and a sleeve, the supporting plate and the die set are disposed onopposite sides of the sleeve, and the cylinder is received in the sleeveand fixed on the supporting plate.
 12. The punch machine as claimed inclaim 1, wherein the pressing member is sleeved on the die core, thecylinder includes a main body and a piston rod, the lower die furtherincludes a top plate and a plurality of top rods, the top plate is fixedto the piston rod, the top rods are fixed to the top plate, the top rodsare passed through the die set, the lower padding plate, and the dieholder in that order, and then connected to the pressing member.
 13. Thepunch machine as claimed in claim 12, wherein the lower die furthercomprises a baffle plate, the baffle plate is sleeved on the die coreand fixed to the top rods, the pressing member is fixed to a surface ofthe baffle plate adjacent to the upper die.
 14. The punch machine asclaimed in claim 10, wherein the upper die further comprises a punchset, an upper padding plate, and a punch plate, the upper padding plateand a punch plate are fixed to the punch set in that order, the punchplate defines a holding hole, the punch core is received in the holdinghole and fixed to the upper padding plate.
 15. The punch machine asclaimed in claim 14, wherein a plurality of guiding posts are fixed to atop surface of the die set, a plurality of outer bushes are fixed to asurface of the punch set, each outer bush defines a dowel hole forengaging with the guiding posts.
 16. The punch machine as claimed inclaim 9, wherein the punch machine further includes a guiding rodconnected to the driving device, the driving device and the guiding rodare disposed on the bracket, the lower die includes a supporting plate,the supporting plate is fixed to the base set of the punch machine, theupper die includes a punch set, and the punch set is connected to theguiding rod.